let A1 = { type: 'div', key: 'A1' };
let B1 = { type: 'div', key: 'B1', return: A1 }
let B2 = { type: 'div', key: 'B2', return: A1 }
let C1 = { type: 'div', key: 'C1', return: B1 }
let C2 = { type: 'div', key: 'C2', return: B1 }
A1.child = B1;
B1.sibling = B2;
B1.child = C1;
C1.sibling = C2;
module.exports = A1;